Composite material



UUA l INU UH ILAS IU.

directly to the studding and headers.

Patented June 15, 1937 UNITED STATES 2,084,232 COMPOSITE MATERIAL RogerW. wmson,

Ruxton, and Guy Leonard,

Baltimore, Md.

No Drawing. Application December 4, 1935,

Serial No. 52,886

3 Claims.

This invention is a composite material preferably in fabricated form,for use in building construction where the material is intended to servein lieu of lath and er and to be applied The components entering intothe composition have been selected to impart the qualities offire-resistance, low thermal conductivity, and o und absorption.

Heretofore, unfired so-called plaster boards or "wall boards and walltiles have been on the market, designed primarily for use in theconstruction of fireproof building walls. Generally these articles maybe grouped into two classes, defined by the character of binderemployed, namely (1) those which employ a sulphate binder such asgypsum, and (2) those which employ a silicate binder, such as hydraulicor Portland cement. The present invention relates to the second class.

The prior art shows it to be old to construct fire-resistant buildingmaterial of non-burning non-metallic inorganic substances, such asasbestos and a binder of hydraulic or Portland cement. Other inorganicfire-resistant substances are also sometimes added to increase theinsulating characteristics and at the same time maintain a low thermalconductivity. However, when the proportion of the cement binder is gagedto insure a workable tensile strength, the proportion of cement withrespect to the other constituents in the commercial mixes is so great asto provide a very hard, more or less brittle material, which is so denseand hard that in sheet form nails or similar fastening devices used forthe purpose of securing the sheets to the wall studding, will fracturethe board or else will bend instead of penetrating. Therefore, holesmust be bored therein for the passage of screws or nails. However,despite that additional labor and cost of installation, the sheet willfrequently fracture during the boring operation, and in practice willalso fracture in the vicinity of said nail holes when the holding strainof the nail is brought to bear upon the slab. In addition to theforegoing, wall boards of this type, with a relatively high proportionof cement content are liable to crack under intense heat and for thisreason are more or less unstable. In view of the characteristicsmentioned, such sheets are not at all adapted for use as cores forveneerlike facings, such as disclosed in an application of Roger W.-Williamson (Serial Number 651,235) now Patent 2,037,294. In addition tothis, if the mix is modified by adding a micaceous material, the boardwill not be so brittle, but in that modifled state it will lack thetensile strength necessary to resist the tendency of the veneer-likefacing to strip from the surface of the core. In other words, there is aproblem of securing a firm bond between the facing and a core of thischaracter.

In practice, it has been found that a mixture of hydraulic or Portlandcement asbestos and a m1caceous material with water, when thoroughlymixed witfl'water' and 1mm: 3 tosetunderres- 10 sure, without firing, ina manner we un ers oo Tfitl'fe art, produces a very hard rigid body,which not only possesses low thermal conductivity and high heatresistant characteristics, but is also of substantial dielectriccapacity.

When the proportion of the micaceous ingredient has been increased withthe intention of imparting to the finished sheet greater softness, aswell as improved insulation quality, the result has been to produce asheet material f lighten 20 weight and a texture so soft "thatiitbecomes frlable'at edgesan'd'at'tho'seplais' where penetrated by nailsand fastening devices. Also its tensile strength is so reduced that thesurface areas will not be suitable for the veneering purposes for whichthis invention is primarily intended, which purpose is mentioned in thenext paragraph.

One of the objects of the present invention is to overcome -the abovementioned difliculties by 0 providing an unfired non-burning orfire-resistant body which may be shaped into any desired form, the samebeing constructed of non-combustible plastic silicates, whereby saidbody will be highly fire-resistant, and normally crack-resistant, but 35will nevertheless possess the characteristic that it may be readilypenetrated by nails and similar sharp securing devices. A further objectis to provide a fire-resistant board-like material which will beparticularly adapted for use as a core for 40 wood veneering and othersimilar ornamental facings, such as described in the Williamsonapplication, supra, in that it will possess the desired softness as wellas the necessary tensile strength and toughness required for thispurpose. A further object is to provide a dry mixture of non-combustiblesilicates including a crack and fracture resistant element, allpossessing the characteristic of becoming plastic when mixed with water,so as to be moldable into any desired 60 shape.

The invention will be hereinafter fully set forth and particularlypointed out in the claims.

In carrying out the invention it is desirable to employ a mixture ofasbestos, a micaceous material, an hydrous aluminum silicate, and asilicate binder, the mixture being made plastic by the addition ofwater, and then molded while in the plastic state.

It is preferred to use asbestos and a micaceous silicate is in the formof vermiculite, zonolite, jeffersite or any of the other equivalent andwell known flateimicasilicates. The toughening or tempering material17am any hydrous aluminum silicate of the kaolin group, but of coursethe best results are obtained by the purest quality. The binder ispreferably in the form of any standard hydraulic or Portland cement.

The proportions of the various materials may be varied as desired butthe following is given as an example:-

Parts by weight Asbestos 30 'Vermiculite 15 Kaolin I 10 Hydraulic orPortland cement 45 In practice, the asbestos, vermiculite, kaolin andcement, which are all dry n us e non-metallic inorganic silicates arethoroughly mixed in any suitable manner, and after they are thoroughlycommingled water is added to produce plasticity.

Whether the core is the product of the mold method, or is made by acontinuous process method is immaterial, and inasmuch as both methodsare well known in the art, and no claim is here made for the method ofmaking and drying the material, these methods will not be referred to ingreater detail.

It is preferred to fabricate the material in the form of relatively thinsheet-like boards, because this is the most desirable form to functionas the supporting cores for veneering. In this form, by reason of thetoughness imparted by the kaolin, it possesses adequate strength andstability for all normal requirements in such capacity, and penetrableby nails and the like. Aside from this, by reducing the volume ofmaterial required, a great saving is eflected in cost of manufacture andoverhead involved in installation.

The asbestos is incorporated because of its known fire-resistantcharacteristics, and thug;- miculite is employed not only becausegf itsfi eresistanfiharacteflstic but also begauseit posses 885thfifid'itiofial; shai tfirisii sg .laiuhai z cometrvity'aridmghnieieetricyalu The asbestos'and the vermiculite are both readilymixed 'with the hydraulic or Portland cement in such a thorough mannerthat the materials may be uniformly distributed throughout the mixturewith small effort. The incorporation of the kaolin in the mix imparts acertain desirable toughness to the. molded material, and at the sametime renders the board less friable at the edges than is possible withthe prior art boards. Notwithstanding this, it tempers the mix so as tomake the board less susceptible to cracking or fracturing, whilepenetrable by nails or the like, all of which is accomplished withoutdestruction or substantial impairment of the tensile strength andfireresistant characteristics of the other materials. In other words,the combination of Portland or other cement with kaolin constitutes atempered silicate binder for the asbestos and the vermiculite. The k aol also tends to counteract excessm gm of the board, due to theincorporagpf. the yri'niculiteyandfor'this'reason it is desirablethatthe proportion of the kaolin'coflten't shall vary with theproportion of the vermigulite. The proportion of the cement is alsopreferably varied in proportion to the amount of kaolin employed.

The advantages of the invention will be readily understood by thoseskilled in the art to which it belongs. For instance, it will beobserved that a board, or other object processed from the mixture abovedescribed will exhibit a very high degree of hardness and toughness andwill also possess many other desirable characteristics such as high fireresistance, and a maximum degree of cohesion under fabrication, withoutbrittleness of body and friability of edges, and yet be susceptible ofpenetration by nails and other sharp devices of similar characterwithout cracks or fractures. Sheets made from the mixture abovedescribed are also valuable as cores for wood veneering and otherornamental surfaces, in that they may be firmly bonded with suchfacings.

This application is a substitute for application Serial Number 651,236filed January 11, 1933 and ofiicially allowed October 1'7, 1934.

Having thus explained the nature of the invention and described anoperative manner of constructing and using the same, although withoutattempting to set forth all of the forms in which it may be made, or allof the forms of its use, what is claimed is:-

1. A composite sheet consisting of an unfired I without danger of bodyfracture.

2. A composite sheet consisting of an unflred non-friable substantiallyhard and tough sheetlike refractory body comprising a mixture of ahydraulic cement binder, asbestos, a foliated micaceous material, and atempering agent consisting of a hydrous aluminum silicate of the kaolingroup, the volume of the tempering agent being so definitelyproportionedto the volume of the foliated micaceous material that saidbody is readily workable with edge tools and penetrable by sharp metalanchoring devices without danger of body fracture.

3. A composite sheet consisting of an unflred non-friable substantiallyhard and tough sheetlike refractory body consisting of a mixture ofapproximately 45 parts by weight of hydraulic cement binder,approximately 30 parts by weight of asbestos, approximately 15 parts byweight of vermiculite and approximately 10 parts by weight of kaolin,the proportion of kaolin with respect to the total mixture being suchthat said body is readily workable with edge tools and penetrable bysharp anchoring devices without danger of body fracture.

ROGER W. WILLIAMSON. GUY LEONARD.

